What is Mallet Finger?

Mallet finger is a common hand injury that occurs when the extensor tendon responsible for straightening the tip of the finger becomes impaired. This condition results in the inability to extend the fingertip, which droops down, resembling a mallet or hammer. It is typically caused by a forceful impact that bends the fingertip, leading to either a tear in the tendon or a fracture of the distal phalanx (the fingertip bone) where the tendon attaches.

Different Types of Mallet Finger

Mallet finger can be classified based on the extent of the injury:

Tendon Injury Only: This type occurs when the extensor tendon is torn or avulsed from its attachment on the distal phalanx, without any associated bone fracture.
Bony Mallet Finger: This involves a fracture of the distal phalanx where the tendon attaches. The fracture may range from a small chip of bone to a larger fragment, depending on the severity.
Complex Mallet Finger: In more severe cases, multiple fractures or associated joint instability may be present. This type may also include a fracture and a tear in the extensor tendon.

Causes of Mallet Finger

Mallet finger is generally caused by direct trauma or impact to the fingertip. Common causes include:

Sports Injuries: Activities including most ball sports where a ball strikes the fingertip forcing the tip to bend. This is common in football, basketball, netball and cricket.
Accidental Injuries: Dropping heavy objects on the fingertip or catching a finger in a door.
Workplace Injuries: Exposure to machinery or tools that cause forceful impacts to the fingers.

Symptoms of Mallet Finger

The primary symptoms of mallet finger include:

Drooping Fingertip: The most visible sign is the inability to straighten the tip of the finger, which remains flexed and drooped.
Pain and Swelling: Pain and swelling around the fingertip area are common immediately following the injury.
Bruising: Discoloration and bruising around the affected area can develop.
Reduced Functionality: Difficulty using the affected finger for gripping or other tasks due to the drooping tip and reduced mobility.

Anatomy

The extensor tendons are the tendons that run along the back of your fingers and help you straighten them. When you have mallet finger, these tendons can be damaged. The distal phalanx is the small bone at the very tip of your finger where these tendons attach. If this bone is fractured, it may make the injury more complicated.

The distal interphalangeal joint is the joint just below the fingertip. In severe cases, this joint can also be affected, which may lead to additional problems with finger movement and stability. In the longer term, if a mallet finger is not treated and the tip of the finger remains bent the nearby joint in the finger can be affected and cause a swan neck deformity. This can lead to a limitation of bending at the proximal interphalangeal joint which is the next joint in the chain. If this occurs it can be quite disabling and difficult to treat.

Treatment and Surgery Options

Non-Surgical Treatment Options

Most cases of mallet finger can be effectively treated without surgery. Non-surgical treatments include:

Splinting: The mainstay of treatment is the use of a splint that keeps the fingertip in a straight position.

For Tendon-Only Injuries: The splint should be worn full-time for about 8 weeks, followed by a night splint for an additional 4 weeks.
For Bone Injuries: The splint is typically worn full-time for 6 weeks, with a transition to a night splint for another 4 weeks.
Custom Splints: Custom-made splints offer a more comfortable and adjustable fit, accommodating changes in swelling and providing effective immobilisation.

Finger Movements: During the splinting period, it is important to keep the other joints in the finger moving to prevent stiffness and maintain overall finger mobility.
Avoiding Drooping: The fingertip must be kept straight while the splint is off. If the tip droops, the splinting period may need to restart, which can prolong recovery.

Surgical Options for Mallet Finger

Surgery is usually reserved for specific cases where non-surgical treatments are inadequate. Surgical options include:

Unstable Fractures: If there is a large fracture fragment or if the joint becomes unstable and dislocates, surgery may be required to realign and stabilise the joint.
Complex Cases: For injuries involving multiple fractures or significant joint instability, surgical intervention may be needed to address these complications and improve outcomes.